This keyboard would map the vocal tract underneath the
fingers, thumbs and wrists so that as much as possible the
operation of the vocal tract in speaking could be simulated by
the fingers, thumbs and wrists. I dont know whether the g
would be on one pinky and the p on the other pinky or if
the g
would be at the wrists and the p at the index fingers, or if
vowells would be up for e and down for o with a spectrum
inbetween or some other configuration but the idea would
just be to experiment as much as possible until you found a
configuration that allowed the user to use a conceptual map
that is as low as possible in the cognitive process, so that
they could as easliy as possible map the process for speaking
onto the keyboard. Could touch screens make this easy?

When I see "vocal tract" I usually think "throat stuff", but I know that the mouth/lips/tongue are quite important parts of the vocalization process.

Ordinary English has more than 30 distinct sounds used in the various combinations for producing words, and most of those sounds are mapped to the alphabet (most of the vowels get two sounds each). A few sounds, like the two "th" sounds of "thin" and "then", are mapped to combinations of alphabet letters.

This Idea doesn't work simply, since most humans only have ten fingers, although of course if combinations of fingers are used, like playing a "chord" on a musical instrument, that would be fine.

I wonder if a long-term benefit might happen, if the Idea became widely used. Imagine a new "alphabet" being designed to be associated with those finger-chords. Then every word in the language could be written using that new alphabet, and the entire language would then become perfectly phonetic.

The linked Voder demo is more interesting expression-wise
than any current synthesized speech project I know of.
How did we lose this?

Maybe the letters of an alphabet could be cartooney
images of the vocal tract with the key areas exaggerated to
simplify, differentiate and represent the shape that makes
the sound.

I wonder if the extra sounds could be mapped onto other
body parts rather than using the "decimal point" of finger
chords, so that the original simple spectrum-like
arrangement of the phonological map is preserved? So
maybe map the spectrum from g to p over the whole body
starting at the feet and using the knees for "k" and the
torso for "sh" and the elbows for "s" and mapping only the
ts, bs, ps etc over the fingers.